Vanadium and Molybdenum Complexes with Amino Acid Functionalized Ligands

210 Pages·2006·2.51 MB·English

Vanadium and Molybdenum Complexes
with Amino Acid Functionalized Ligands
DISSERTATION
zur Erlangung des akademischen Grades doctor rerum naturalium
(Dr. rer. nat.)
vorgelegt dem Rat der Chemisch-Geowissenschaftlichen Fakulta¨t der
Friedrich-Schiller Universit¨at Jena
von Food Chemist Manjola Mancka
geboren am 17.04.1978
in Devoll, Albania
Gutachter
1. Prof. Dr. Winfried Plass
2. Prof. Dr. Matthias Westernhausen
Tag der o¨ffentlichen Verteidigung: October 18th 2006
For my beloved parents and my Family
Acknowledgements
• I would like to express my heartfelt gratitude to my supervisor Prof. Dr. Winfried
Plass for giving me the opportunity to work in this interesting field, I thank him
for support, advises and guidance.
• I also thank to Dr. Axel Buchholz, for many valuable suggestions, for much help
in the single crystal analysis, and for his help in the arrangement of the thesis.
• I am grateful to our research group with whom I had the pleasure of working,
for their friendship, helpful discussions, and the good co-operative atmosphere. I
also thank to my colleague Arne Roth for helping me in solving LATEX problems.
I would like to thank Ines Seidel for many valuable discussions about the kinetic
experiments.
• I moreover thank all Technical assistants of the Institut fu¨r Anorganische und Ana-
lytische Chemie (IAAC) and NMR department for analyses of the samples: Dr.
Popitz, Frau Scho¨nau und Frau Heineck (MS), Frau Rambach und Dr. Friedrich
(NMR, EPR), Frau Lentvogt und Frau Scho¨nfeld (CHN).
• Many thanks to Lotte Neupert for the HPLC measurements.
• I am especially pleased to acknowledge Dr. Helmar Go¨rls for measuring my X-ray
crystal structures.
• Finally, I would like to thank my parents Seri and Hava, my sisters Anila and
Amoleza, as well as my brother Ardi, especially my husband, Anton, for their con-
tinued moral support, patience and encouragement. They are the most important
people in my life and they have been with me every step of the way.
Contents
1 Introduction 11
1.1 History of vanadium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.2 Vanadium haloperoxidases . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.3 Phosphate-Vanadate-Analogy . . . . . . . . . . . . . . . . . . . . . . . . 19
1.4 Structural models for vanadium-dependent
haloperoxidases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.5 Design of new ligand system . . . . . . . . . . . . . . . . . . . . . . . . . 22
1.6 History and occurrence of molybdenum . . . . . . . . . . . . . . . . . . . 23
2 V(v)-Complexes with Boc-L-α-amino acid ligands 27
2.1 Synthesis and Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.2 Structural characterization . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.3 Spectroscopic Characterization . . . . . . . . . . . . . . . . . . . . . . . . 36
2.4 Reactivity of the complexes . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.4.1 Bromination reaction of TMB/MCD . . . . . . . . . . . . . . . . 39
2.4.2 Catalytic oxidation of sulfides catalyzed by
cis-dioxovanadium(v) complexes . . . . . . . . . . . . . . . . . . 40
2.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
2.6 Experimental Part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.6.1 Synthesis of the Schiff base ligands with Boc-L-α-serine residue . 45
2.6.2 Synthesis of N-salicylidene-Boc-L-α-histidine-hydrazide
(HsalhyBochis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.6.3 Synthesis of the Schiff base ligands with
Boc-L-α-tryptophan residue . . . . . . . . . . . . . . . . . . . . . 48
5
6 CONTENTS
2.6.4 Synthesis of the Schiff base ligands with
Boc-L-α-phenylalanine residue . . . . . . . . . . . . . . . . . . . . 50
2.6.5 Synthesis of cis-dioxovanadium(v)-complexes with Boc-L-α-serine
residue ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
2.6.6 Synthesisofcis-dioxovanadium(v)-complexeswithBoc-L-α-histidine
residue ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
2.6.7 [VO (HsalhyBochis)] (5) . . . . . . . . . . . . . . . . . . . . . . . 56
2
2.6.8 Synthesisofcis-dioxovanadium(v)-complexeswithBoc-L-α-tryptophan
residue ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
2.6.9 Synthesisofcis-dioxovanadium(v)-complexeswithBoc-L-α-phenylalanine
residue ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
2.6.10 SynthesisofmonooxovanadiumcomplexeswithphenylalanineSchiff
base ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
2.6.11 Catalytic oxidative bromination of TMB/MCD . . . . . . . . . . 63
2.6.12 General procedure for preparation of chiral sulfoxides: . . . . . . . 64
3 V(v)-complexes with free L-α-amino acid ligands 65
3.1 Synthesis and Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.2 Structural characterization . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.2.1 Complexes with phenylalanine residue (18) . . . . . . . . . . . . . 71
3.2.2 Complexes with tyrosine residue (20a and 20b) . . . . . . . . . . 76
3.2.3 Comparison of the structures 18 and 20b . . . . . . . . . . . . . . 81
3.2.4 Unprecedented complex 21 . . . . . . . . . . . . . . . . . . . . . . 81
3.3 Spectroscopic Characterization . . . . . . . . . . . . . . . . . . . . . . . . 88
3.4 Reactivity of the complexes . . . . . . . . . . . . . . . . . . . . . . . . . 92
3.4.1 Oxidative bromination of
1,3,5-trimethoxybenzene/monochlordimedone . . . . . . . . . . . 92
3.4.2 Oxidation of sulfides catalyzed by cis-dioxovanadium complexes
with free amino acid functionalized ligands . . . . . . . . . . . . . 94
3.4.3 Spectrophotometric titration . . . . . . . . . . . . . . . . . . . . . 95
3.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
CONTENTS 7
3.6 Experimental Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
3.6.1 Synthesis of the Schiff base ligands with L-α-leucine residue . . . 97
3.6.2 Synthesis of the Schiff base ligands with L-α-phenylalanine residue 99
3.6.3 Synthesis of the Schiff base ligands with L-α-tyrosine residue . . . 103
3.6.4 Synthesisofcis-dioxovanadium(v)-complexeswithL-α-leucineresidue
ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
3.6.5 Synthesisofcis-dioxovanadium(v)-complexeswithL-α-phenylalanine
residue ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
3.6.6 Synthesisofcis-dioxovanadium(v)-complexeswithL-α-tyrosineresidue
ligands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
3.6.7 Unprecedented obtaining complexes . . . . . . . . . . . . . . . . . 114
3.6.8 Catalytic oxidative bromination of TMB/MCD . . . . . . . . . . 117
3.6.9 Catalytic oxidation of methyl phenyl sulfide: . . . . . . . . . . . . 118
4 V(v)-complexes with L-β-alanine ligands 119
4.1 V-complexes with Boc-L-β-alanine . . . . . . . . . . . . . . . . . . . . . 120
4.1.1 Spectroscopic Characterization . . . . . . . . . . . . . . . . . . . 121
4.1.2 Reactivity of the complexes . . . . . . . . . . . . . . . . . . . . . 123
4.2 Complexation studies using free β-alanine ligand . . . . . . . . . . . . . . 126
4.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
4.4 Experimental part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
4.4.1 Synthesis of Schiff base ligand with Boc-L-β-alanine . . . . . . . . 128
4.4.2 Synthesis of vanadium complexes with Boc-L-β-alanine . . . . . . 130
4.4.3 Synthesis of Schiff base ligand with L-β-alanine . . . . . . . . . . 131
4.4.4 Attempted synthesis of vanadium complexes with L-β-alanine . . 133
4.4.5 Catalytic oxidative bromination of TMB/MCD . . . . . . . . . . 134
4.4.6 Catalytic oxidation of methyl phenyl sulfide . . . . . . . . . . . . 134
5 Mo(VI)-complexes with Boc-amino acid ligands 136
5.1 Molecular structure of complex 36 . . . . . . . . . . . . . . . . . . . . . 137
5.2 Spectroscopic Characterization . . . . . . . . . . . . . . . . . . . . . . . . 140
5.3 Sulfoxidation reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
8 CONTENTS
5.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
5.5 Experimental part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
5.5.1 [MoO (salhyBocser)] (31) . . . . . . . . . . . . . . . . . . . . . . 144
2
5.5.2 [MoO (salhyBoctrp)]·Et O (32) . . . . . . . . . . . . . . . . . . . 145
2 2
5.5.3 [MoO (salhyBocphe)] (33) . . . . . . . . . . . . . . . . . . . . . . 146
2
5.5.4 [MoO (BrsalhyBocphe)] (34) . . . . . . . . . . . . . . . . . . . . . 147
2
5.5.5 [MoO (MesalhyBocphe)] (35) . . . . . . . . . . . . . . . . . . . . 147
2
5.5.6 [MoO (salhyBocala)(MeOH)]·2MeOH (36) . . . . . . . . . . . . . 148
2
5.5.7 Catalytic oxidation of methyl phenyl sulfide: . . . . . . . . . . . . 149
6 Mo(VI)-complexes with free amino acid ligands 151
6.1 Structural characterization . . . . . . . . . . . . . . . . . . . . . . . . . . 152
6.1.1 Mo-complex with leucine residue (37) . . . . . . . . . . . . . . . . 152
6.1.2 Mo-complex with phenylalanine residue (39) . . . . . . . . . . . . 155
6.1.3 Mo-complex with tyrosine residue (42) . . . . . . . . . . . . . . . 157
6.2 Spectroscopic Characterization . . . . . . . . . . . . . . . . . . . . . . . . 163
6.3 Sulfoxidation Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
6.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
6.5 Experimental part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
6.5.1 [MoO (Brsalhyleuacac)(MeOH)] (37) . . . . . . . . . . . . . . . . 167
2
6.5.2 [MoO (Mesalhyphe)] (38) . . . . . . . . . . . . . . . . . . . . . . 167
2
6.5.3 [MoO (Mesalhypheacac)(MeOH)]·2MeOH (39) . . . . . . . . . . . 168
2
6.5.4 [MoO (Brsalhyphe)(MeOH)]·H O (40) . . . . . . . . . . . . . . . 169
2 2
6.5.5 [MoO (Mesalhytyr)]·2H O (41) . . . . . . . . . . . . . . . . . . . 169
2 2
6.5.6 [MoO (Mesalhytyracac)(MeOH)]·2MeOH·Et O (42) . . . . . . . . 170
2 2
6.5.7 Catalytic oxidation of methyl phenyl sulfide . . . . . . . . . . . . 171
7 Summary 172
8 Characterization techniques 180
8.1 Elemental analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
8.2 NMR spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
CONTENTS 9
8.3 Mass spectrometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
8.4 Infrared spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
8.5 UV-Vis measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
8.6 HPLC analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
8.7 Crystal structure analyses . . . . . . . . . . . . . . . . . . . . . . . . . . 181
8.8 General Remarks: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
I Crystallographic data 183
II Abbreviations 193
10 CONTENTS